The RNA expressed by cells transfected with the fusion oncogene, ovc, originally isolated following transfection of DNA from the human ovarian carcinoma cell line, OVCAR-3, has been analyzed. The major 2.9 kb message hybridizes to chromosome 9 sequences containing the major 140 amino acid open reading frame, but not to adjacent sequences. RNA synthesis proceeds from chromosome 9-specific sequences into chromosome 8, and the bulk of the chromosome 9-specific DNA has been lost from cells which retain their transformed phenotype and RNA expression. The results are consistent with the chromosome 9 sequences encoding the 5'-specific portion of the mRNA. Collaborations continue on efforts to detect and identify oncogenic sequences present in fish tumors. The nude mouse tumor assay has detected two candidate transforming sequences, and initial analysis of clones containing transfected sequences from one of these indicates they represent previous sequences not related to sequences in the DNA database.